Rotor of an electric motor

Abstract

The invention relates to a rotor (30) of an electric motor having a shaft (33) and a magnet (32) disposed on said shaft (33), wherein the magnet (32) is attached to the shaft (33) using an injection molded plastic material and the plastic material forms a cooling vane (31) which generates a cooling air flow when the rotor (30) is in operation.

The invention claimed is: 
     
       1. A rotor of an electric motor having a shaft and a magnet disposed on said shaft,
 wherein the magnet is attached to the shaft using an injection molded plastic material and the plastic material forms a cooling vane, the cooling vane generating a cooling air flow when the rotor is in operation, 
 wherein the cooling vane comprises a plurality of cooling blades, the plurality of cooling blades forming a blade ring; 
 wherein the cooling blades are curved in an axial top view; 
 wherein the cooling vane comprises a balancing rim indirectly or directly adjacent to the magnet, 
 wherein a duct is formed between the magnet and the shaft, 
 the duct establishes a connection between two opposite axial sides of the magnet and is filled with the plastic material that forms the cooling vane; 
 wherein the magnet comprises a recess, which is on a side opposite the cooling vane, and filled with the plastic material that forms the cooling vane and the magnet is partially uncovered by the plastic material; and 
 wherein the maximum outer circumferential diameter of the cooling vane is smaller than the maximum outer circumferential diameter of the magnet, such that the magnet is partially uncovered by the cooling vane circumferentially and radially. 
 
     
     
       2. The rotor according to  claim 1 , wherein axial front sides of the cooling blades are completely free and uncovered. 
     
     
       3. The rotor according to  claim 1 , wherein the cooling vane can be demolded in an axial direction. 
     
     
       4. The rotor according to  claim 1 , wherein the balancing rim comprises at least one milled-out portion or recess or a balancing weight. 
     
     
       5. The rotor according to  claim 1 , wherein the cooling vane and the magnet are immediately adjacent in the axial direction. 
     
     
       6. The rotor according to  claim 1 , wherein the cooling vane defines an axial free end of the rotor. 
     
     
       7. The rotor according to  claim 1 , wherein the magnet is attached to the shaft by injection molding using the plastic material which forms the cooling vane. 
     
     
       8. The rotor according to  claim 1 , wherein the cooling vane, the magnet, and the shaft form a single-piece unit connected by the plastic material. 
     
     
       9. The rotor according to  claim 1 , wherein the plastic material encloses at least portions of the magnet from both axial sides, such that the plastic material fixes the magnet to the shaft. 
     
     
       10. An electric motor having a rotor according to  claim 1 .